1. Field of the Invention
The present invention relates to an apparatus for discharging a waste gas in a semiconductor manufacturing process. More particularly, the present invention relates to an apparatus for discharging a waste gas in a semiconductor manufacturing process, which can keep constant the amount of purge of nitrogen for inducing the waste gas to discharge while increasing a temperature of the waste gas so that dust of the waste gas is not accumulated on the inner wall of a pipe, and prevent an accident such as a burn from generating in workers.
2. Related Prior Art
Generally, in a semiconductor manufacturing process, for example, a wafer treatment process, an oxide film is formed on a wafer by supplying a various kinds of reaction gases to a wafer disposed within a chamber. Such reaction gases are highly noxious and are thus fatal to the human body. Further, there is a possibility that they may explode when being mixed with other gases or air. Therefore, they have to be converted into harmless gases through reaction and be then discharged.
FIG. 6 shows a system for discharging those waste gases after reaction. A reaction gas within a chamber 10 for processing a wafer is discharged through a vacuum pump 12. The gas is burnt and purified by a gas scrubber 16 connected to an exhaust line of the vacuum pump 12 through a valve 14.
In such a waste gas discharge system, however, as the valve 14 employs a mechanical open/close mode by a Bellows, etc. using pneumaticity, the valve 12 is damaged by solidification of dust due to the cooling of the waste gas. For this reason, there is a problem that the process is stopped. Furthermore, if the exhaust line to the gas scrubber 16 is increased, the waste gas is cooled while moving to the exhaust line. Thus there is a danger that the exhaust line may be closed due to solidified dusts. In order to prevent this, an additional processing device must be installed in the exhaust line. This makes the structure complicated.
Considering this problem, the present applicant proposed the Korean Utility Model No. 209874 entitled xe2x80x9cWaste Gas Inducing Devicexe2x80x9d as shown in FIG. 7. As seen in FIG. 7, this device includes an inlet transfer 20 having an inlet port 22 on its outer circumferential face, a discharge transfer 30 inserted into the inlet transfer 20 with an O-ring 34 intervened between them, so that a blow-off gap 32 communicating with the inlet port 22 is formed between the inner circumferential face of the inlet transfer 20 and the bottom of the discharge transfer 30, a heating casing 40 installed around the inlet transfer 20 to form a heating room 42 and having a nitrogen inlet port 44 formed an outer circumferential face, an electric heat wire 50 surrounding the inlet transfer 20 within the heating room 42, and a temperature sensor 60 disposed at the exit of the discharge transfer 30 for controlling a temperature of the electric heat wire 50.
The device may be disposed between the chamber and the vacuum pump, and at the front or rear stage of a subsequent exhaust line or the gas scrubber in the vacuum pump. According to this device, if nitrogen is forcibly sent to the heating room 42 through the nitrogen inlet port 44, nitrogen is heated by the electric heat wire 50 and is then blown off into the discharge transfer 30 through the inlet port 22 and the blow-off gap 32. The blown-off nitrogen is mixed with the waste gas introduced via the inlet of the inlet transfer 20, thus keeping high a temperature of the waste gas so that it is not cooled. Accordingly, dusts of the waste gas are prevented from being stacked. Furthermore, such nitrogen functions to increase the amount of the waste gas introduced into the inlet transfer 20 by means of a purge discharge through the blow-off gap 32.
In the conventional device, however, as the discharge transfer 30 is fixed to the inlet transfer 20 by means of the O-ring 34 in order to keep the blow-off gap 32, the blow-off gap 32 is changed due to fluctuation of the discharge transfer 30. For this reason, the amount of purge of nitrogen is not uniform. As a result, there is a problem that the blow-off gap 32 keeps unstable due to nitrogen. In addition, as a hot heating casing 40 is exposed outwardly, there is a danger that a worker may be burnt while touching the heating casing 40.
Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an apparatus for discharging a waste gas in a semiconductor manufacturing process, which can keep constant the amount of purge of nitrogen for inducing the waste gas to discharge while increasing a temperature of the waste gas so that dust of the waste gas is not accumulated.
Another object of the present invention is to prevent an accident such as a burn, etc. from generating in workers.
According to a preferred embodiment of the present invention, there is provided an apparatus for discharging a waste gas in a semiconductor (or TFT-LCD) manufacturing process, including an inlet transfer having an inlet port disposed at its outer circumferential face and a support rib disposed at its inner circumferential face; a discharge transfer having a support jaw fixed to a support rib at its outer circumferential face, wherein the discharge transfer is inserted into the inlet transfer so that a blow-off gap communicating with the inlet port is formed between the bottom of the discharge transfer and the inner circumferential face of the inlet transfer and a high-pressure gas room communicating with the inlet port and the blow-off gap is formed between the outer circumferential face of the discharge transfer and the inner circumferential face of the inlet transfer; a transfer cap having the bottom coupled to the top of the inlet transfer, while surrounding the discharge transfer; a heating casing disposed around the inlet transfer and the transfer cap to form a heating room, and having a nitrogen inlet port disposed on its outer circumferential face; an electric heat wire disposed within the heating room; and a temperature sensor for controlling a temperature of the electric heat wire.
According to the present invention, a burn-preventing cap surrounding a heating casing may be further provided with a given distance from the outer circumferential face of the heating casing.